Hammer mill



July 15, 1930. w. E. VAN con HAMMER MILL Filed Jan. 27, 1927 WITNESSES A TTORNE Y.

i Patented July 15, 1930 y UNITED STATES PATENT 4OFFICE 'WILBUR E. VAN GOTT, OF MILWAUKEE, WISCONSIN HAMMER MILL n Application-ined January 27, 1927. Serial No. 164,018.

The invention relates to hammer mills and Fig. 6 is a detail elevation of a casing lockthe like and to the impact hammers included ing and releasing device. in such mills. In these drawings, the numeral 10 desig- An object of the invention is to provide an nates a lower casing and the numeralll a suimpact hammer in the formof a substantially perposed upper casing, the latter being pro- 50 circular member having a cutting periphery vided With ears 12 by Which it is pivotally and capable of being pivotally mounted in mounted at the ends of a bolt 13 on the lower several successive positions to present fresh casing 10. The lower casing l0 includes a impact surfaces When needed, thereby afp aii' ofspaced parallel end plates 14 profording long and economical service, vided With mounting flanges 15 adapted to be 55 Another object-of the invention is to form secured to suitable supports 16, and an outer the circular member as an annular disk Withy Shell 17 is interposed between the end lates a, row 0f pivot, Openings placed therein, and clamped therebetween the bolli', 3 and A further object is to provide a, hammer other similar b olts 18 surrounded by tubular mill rotor assembly in which the hammers are SPaCeIS 19 Which laterally bear against the '60 S0 disposed as t0 minimize Vibration under' 0111281 S'llIfCe 0f Shell. 111-1191 51191120 high speed operation and to reduce windage of senil-oval shape is placed Within the outer losses. shell 17 to rest thereagainst at its bottom por- A further object, is to provide a hammer tionand is provided With inturned flanges 21 2o mill including a casing constructed of heavy at lts Upper ends SCUFed t0 Slmllar lntlllned 65 sheet metal or plate to reduce the liability flanges 22.03 the Outer Shell 171 FeenfOvlClIlg of failure in use, a reenforcing lining being bars 23 belng Secured as by Yetllgi t0 each included in the casing to take Wear and to URPGI" flange 22 alhacent lthe inner edge of form abutments for receiving a removable Sald Hnge;

25 screen 4and'other casing elements. A semicircular liner plate 24 is secured-,1'70V A further object is to provide a hammer as by TWG/'0mg 01' Weldllfl t0'tl2e-1f111e1 face mill including a pivotally mounted top casing 0f @Ch end P121te 14 and a Semlcllcull" br' and actuating means for locking and Opening 25 1S SeCllle-d 1Z0 endl elIlCl plate t0 OI'111-- the top Casing, a semicircular screen-receiving groove 26 be 3ov The invention further consists in the sev- WGGII PfaCll bar and the curved edge portions 75 eralv features hereinafter set forth and more 0f the adJaCellt liner plltei, 21S Seen in Figs. particularly defined by the annexed claims. 1 and 4- A Semlcyllldflcl SCIBCH Shell 27 In the accompanying drawings7 Fig, 1 is n,` of heavy sheet metal is interposed between the transverse sectional elevation of e hammer end plates 14 und has its opposite edges fitting mill embodying the invention; Within the grooves 26, the screen shell being" S0 Fig. 2 is a fragmentary'longitudinal eleve readily removable from the grooves, as heretion of the hammer vmill taken on the line inafter described, when itisnccessary to make 2-2 of Fig. 1; Y v replacements either bccnuseof Wear or in oi'- 3 is a detail view of one of the hanider to provide a different size of screen open- 40 mers; ings. The upper edge ot' each liner plate 21 5;,

Fig. 4 is a detail sectional view of one end terminates short of the upper edge of the portion of the casing; adjacent end plate 14 to form a rabbct und Fig. 5 is a schematic development vieuT both plates are provided at intermediate showing the manner of mounting the hamportions of their upper edges with concenmers on the rotor, and tric semicircular notches 28 to receive tliere- 9o through the shaft 29 of a rotary hammer assembly hereinafter described.

The up er casing 11 includes end plates 30 of heavy s eet metal secured together by bolts 31 some of which pass through tubular spacers 32. Curved casing shells 33 and 34 are interposed between the end plates 30, the outer surface of the shell 33 being engaged by the spacers 32. A liner plate 35 is secured, as by rlveting or welding, to the inner face of each end late 30 and forms abutments at some of its e ges receiving the inner edge portions of the casing shells 33 and 34. The end plates 30 and liner plates 35 are also provided with concentric semicircular notches 36 registering with the notches 28 in the lower casing to form circular openings for the shaft 29. The lower edge of each liner plate 35 projects below the lower edge of the adjacent end plate 30 in order to project below the upper edge of the end plates 14 of the lower casing, as seen in Fig. 4, thereby providing an overlapping relation which insures good alignment of the upper and lower casings and affords additional reenforcement.

When the upper and lower casings are together in the position of Fig. 1, the lower edges of the shells 33 and 34 in the u per casing bear against the upper edges o the screen shell 27v to prevent its displacement, the bars 23 secured to the shell 17 of the lower casing serving to align the inner surface of the shells 33 and 34 with the inner surface of the screen shell 27 and also serving to reenforce the shells 33 and 34 against outward deformation.

The casing shell 34 is concentric with the screen shell 27, While the casing shell 33 is formed with a greater radius of curvature and is spaced from the upper end of the casing shell 34 to provide an intake opening into which projects a deliver chute 37 pivotally 4mounted at its inner en onone of the bolts 31 to permit its placement at various inclinations. A late 38 is pivotally suspended from one o the bolts 31 near an upper-corner of the ufpper casing and projects into the chute to orm an inwardly-swinging door displaceable by material passing down the chute. A discharge opening 39 is formed in one end plate of the lower casing 10, the lower edge of the opening bein flush with the bottom of the inner casing she l 20. In order to remove material from the shell, suction is applied to the opening 39.

The shaft 29 extending through the casing assembly is driven at high speed from any suitable source of power and has mounted thereon a series of spaced disks 40 preferably of heavy steel plate, the disks being secured to the shaft 29 by-means of a pair of opposite keys 41 to insure against loosening. The disks 40 are held in spaced relation by interposed spacing rings 42 and the entire disk assembly is clamped etween nuts 43 threaded onto the shaft. The disks 40 are provided near their periphery with a circular series of bores 44 dis osed in alignment through the series of disks, and a number of equally spaced removable pivot bolts 45 extend through the openings 45 in parallel relation to the axis of the shaft 29. f

The hammers of this invention consists of ratchet-like annular disks 46 of wear-resisting metal, such as manganese steel, one of the hammers being shown in detail in Fig. 3. Each disk 46 is provided with a clentral aperture 47 aboutl which is formed a circular group of pivot openings 48 preferably numbered to facilitate resetting, as hereinafter described.

yThe peripheryv of the disk presents a serrated appearance produced by impact teeth 49 of suitable shape and pitch according to the service in which the disk is used. In the present instance, each tooth is shown to have an abrupt impact shoulder 50. The provision of the central aperture 47 and the surrounding apertures and recess 48 serves to reduce the weight of the disk and the resulting centrifugal stresses when the disk is in use. Each disk/thus presents the appearance of an annular ratchet wheel.

In constructing the rotor assembly, each pivot bolt 45 is inserted in its position through the aligned openings 44 in the rotary disks- 440 and during its insertion a series of the hammer disks 46 are interposed between the rotary disks 40 in order that the bolt 45 may pass throu h one of the openings or recesses 48 in each ammer disk. When installing a new set of hammer disks, the pivot bolts are passed through the No. 1 openings of the disks. In order to properly balance the rotor assembly, the same number of hammer disks are mounted on each bolt 45. To further facilitate balancing, it is desirable to have each pivot bolt symmetrically loaded by the disks and this is accomplished by disposing the hammer disks on the rotor in converging'rows as indicated in the schematic development view of Fig. 5. In this disposition the disks are arranged along two turns of a helix at each half of the rotor assembly, the helices at opposite ends of the rotor being of opposite hand.

In order to lock therupper casing in registering relation on thel lower casing to enclose the rotor assembly therein, the locking mechanism of Fig. 6 is provi-ded, which includes a pair of levers 5l pivotally mounted at intermediate portions on the end plates 30 of the upper casing 11, the levers being conveniently mounted on the ends of the lowermost bolt l'adjacent the lower end of the shell 33. Each lever 51 includes a hookshaped cam end 52 which is adapted to enter an opening 53 in a bracket 54 secured ynear at a suitable high rate of speed, which causes f sharp the upper end of the adjacent end plate 14 of the lower casing. The cam end 52may also be provided with a terminal threaded portion to receive a hand wheel nut 55 by which the lever may be securely retained in locking position. When it is necessary to lift the upper casing 11 to gain access to the rotor for the purpose of changing hammers, or for other reasons, the levers 51 are employed as pry bars to release the upper casin from the lowercasing, this being accomplis ed by the engagement of the levers with the upper edges of the bracket 54, as' seen in the dotted line position of Fig. 6.

The rotor shaft 29 1s mounted on suitable anti-friction bearings 56, one being shown,

and the same shaft :may be employed to drive the usual suction fan, not shown, for applying suction to the lower casing.

In operation, the rotor assembly is revolved the hammer disks 46 to extend radially outwardly under the infiuence of centrifugal force. Material then int-roduced into the upper casing 11 through the chute 37 falls into the path of the hammer disks and is struck blows by the outer toothed portions of the disks, which serves to break or crush the material into small particles. The broken particles are then shifted out through the openings of the screen shell 27 and are removed by suction through the opening 39.

After a period of service, the outer toothed portions of the hammer disks become worn and ineective and the disks are then removed from their pivot bolts and replaced on the rotor assembly with the pivot bolts passing through their No. 2 openings, thereby presenting fresh cutting teeth at the outermost portions of the disks. After further service the hammer disks may again be reset by successively using the openings No. 3 to No. 8. In this manner, the useful life of each hammer disk is made unusuall long to provide economical operation. Ify

bolts, the bolts may then be replaced in the adjacent heretofore unused openings, thereby minimizing repairs and replacements.

While the hammer disks 46 are shown to be comparatively thin, they may be of any desired width depending upon the service in vwhich they are to be used and may, in some instances, resemble toothed cylinders. It will 'be seen that the deflection of the disks under impact does not change the effective relation of the cutting portions with the material undergoing crushing or grinding, as the cuttin teeth extend" about the periphery of the the openingsV 44 should become unduly worn by the pivot the grinding of grains, ensilage, linseed cake and man other materials, but by suitable modification the mill is also ca able of operatior on harder substances, suc as stone and coa The liners 24 and 35 on the end plates of the casing not only provide reenforcement and a wear-resistin y.surface but obviate the presence of expose rivets within the hammer chamber near the periphery of the hammers, where it is found that the abrasive action incident to the cutting operation is such as to loosen and force out the rivets. If rivets are employed they may be placed closer to the axis and out of the range of the abrasive` action or they may be replaced by spot welding, which is feasible with sheet metal construction.

The term hammer mill is herein employed to designate any one of a variety of 2. In a hammer mill, a rotor comprising a shaft having a plurality of axially-spaced members mounted thereon, a plurality of equally spaced hammer-supporting bolts carried on said members and arranged in parallel relation to the axis of said shaft, a

plurality of pairs of hammers pivotally mounted on each bolt, and each pair of hammers having the same spacing on the several bolts axially of the bolts, there being an equal number of hammers on each bolt s mmetrically loaded thereon and the sets of ammers on any one bolt having different axially spaced planes of rotation from the sets of hammers on adjacent bolts.

3. In a hammer mill, a rotor comprising a shaft having a plurality of axially-spaced members mounted thereon, a plurality of equally spacedhammer-supporting bolts carried on said members and arranged in parallel relation'tol the axis of said shaft, a plurality of pairs of hammers pivotally mounted on each bolt and each pair of hammers having the same spacing on the several bolts axially of thebolts, the hammers on said bolts being disposed in helically arranged series with respect to the axisof'said rotor, there being an equal number of hammers on each bolt symmetrically loaded thereon, and the helical relation of the spaced sets of hammers on one end portion of the rotor being opposite in hand to that on the other end portion of the rotor.

4. In a hammer mill, the combination, wlh a rotor, of upper and lower registering casings enclosing said rotor, each casing including end plates and interposed casing shells, and vWear-resisting liner plates fixedly carried by the end plates of said upper and lower casings and having their adjacent edges out of register with the edges of said end plates to provide an overlapping joint at the meeting edges of said Casin s, said liner plates lneetlng edgewise Within t e casings to avoid the existence of a ledge along said 'oint, whereby to prevent concentrated Wear o said liner plates along said joint.

In testimony whereof, I aix my signature.

VILBUR E. VAN GOTT. 

